Earth, the water planet

Fig. 2.40 . Almost three quarters of the Earth's surface is covered by water, as suggested by this view of the North Pacific Ocean. Earth is the only planet in the solar system where substantial amounts of water exist in all three possible forms - gas (water vapor), liquid and solid (water ice). Here white clouds of water ice swirl near Alaska. The predominantly white ground area, consisting of snow and ice, is the Kamchatka Peninsula of Siberia. Japan appears near the horizon. From this orientation in space, we also see both the day and night sides of our home planet. (Courtesy of NASA.)